Ignition apparatus fob fluid



Aug. 18, 1936. F o, COLE IGNITION APPARATUS Fon FLUID FUEL BURNERS vFiled June .2, 1935 Patented Aug. 18, 1936 UNITED STATES PATENT OFFICE IGNITION APPARATUS FOR FLUID I' FUEL BUBNEBS Frank 0. Cole, Detroit, Mich., assigner to The Timken Silent Automatic Company, Detroit, Mich., a corporation of Michigan Application June 2, 1933, Serial No. 673,948 i 11 Claims. (Ci. 175-115) electrodes which are located near the outer boty tom corner of the combustionchamber and effectively insulated from each other. In this location, the electrodes are exposed to intense heat and, when the insulation material gets hotter 1U than 500 F. to 700 F. varying with the material. it is liable to lose temporarily much of its insulating value, although it recovers such value on cooling. During such temporary loss of insulating value and consequent leakage of current, the electrical system will not generate the spark necessary for ignition of the fuel` but is temporarily inoperative.

'I'he principal object of the present invention is to overcome such tendency of the ignition system to become temporarily inoperative under the influence of heat. The invention consists principally in an elongated hollow walled cover of insulating material for the electrode which is mounted in and extends outwardly through and beyond the hearth or adjacent portion of the combustion chamber. It also consists in the parts and in the combinations and arrangement of parts hereinafter described and claimed. l In the accompanying drawing, wherein like 30' reference numerals refer to like parts wherever they occur,

Fig. 1 is a view partly in vertical section through a burner of the rotary wall llame type showing one of'its electrodes conforming to my. invention; a5 and 4 Fig. 2 is a view of such electrode with my insulating cover thereon. l

The burner illustrated in the accompanying drawing comprises al hearth i, a surrounding 40 wall 2, a metallic combustion or iiame ring 3 in the angle between the hearth l and the wall 2 of the combustion chamber, electrodes 6, extending upwardly through. the bottom 'oi the hearth, electrodes 4 secured to said combustion ring opposite the spark ngers of the respective electrodes 5 and in circuit with a suitable so'urce of electricity, and rotary means 6 at the center of the hearth for spraying liquid fuel towards said combustion ring. Two pairs of electrodes are illustrated but in many installations one pair is sufficient. The burner or combustion ring 3 is preferably of sheet metal and the outer electrode 4 of each pairmay be a block oi' carborundum or 5 the like mounted in a metal pocket 4a welded to the outer face of said ring 3, the ring having an opening to expose the electrode 4. y

'I'he two pairs of electrodes are connected in series. The metal ring 3 being an electrical conductor, wiring that would otherwise be required o is dispensed with. Each inner electrode 5 is connected with a suitable source of electric current. the metal combustion ring completing the circuit.

According to the present invention, the inner electrode 5 of each pair is encased in a c over of 10 insulating material. Sillimanite is especially suitable for such use because it retains its insulating ability up to higher temperatures than porcelain and other insulation materials commonly used. yw

The cover of insulating material comprises an elongated inner cylindrical sleeve or stem i and a cylindrical cup or shell 8 concentric with saldi sleeve but spaced therefrom except at thev bottom or outer end oi. the shell, where the two are in- 20 tegrally united or otherwise secured together. As best shown in Fig. 2, the top of the stem i may be covered by a washer la held in place by nibs 'ib on the electrode 5. The shell is mounted in the side or bottom wall of the combustion chamber near the lower outer corner thereof. Preferably, it is mounted in an upright position in the hearth and extends from slightly above the hearth to a considerable distance below the upper surface oi the hearth and preferably entirely through the hearth. This arrangement places `the inner end of the electrode in the location desired for ignition of the fuel but exposed to intense heat, which may temporarily render the uppermost portion of the insulating material ineffective for its purpose. However, the annular chamber or space between the inner sleeve and the outer shell of insulating material prevents leakage of the current through the upper portion of the insulating material, w ile the integral ccnnection of the sleeveand t e shell is so far away that it remains cool enough .to eiectively insulate the electrode. Consequently,v the ignition system remains continuously responsive to itsY duty even when the upper portion of the insulating ma? terial is rendered temporarily inoperative by excessive heat; and thus the ignition system is not subject to the delays heretoforeA required for the cooling of the insulating material suiiiciently to restore it to operative condition.

What I claim is:

l. The combination with a combustion chain--v berlfor oil lburners of the rotary wall llame type of an electrical ignition system having electrodes in said chamber separately mounted and insu 66 tends through the hearth and an elongated shell surrounding said sleeve and connected to said sleeve outsiderof said hearth but otherwise spaced therefrom.

3. An electrode construction for oil burners of the rotary wall flame type including a hearth and an impact wall against which the fuel is projected, which comprises an insulator cup extending through said hearth adjacent tosaid impact wall, the bottom of said cup being spaced from the bottom of said hearth, an insulator stem extending through said cup and secured in the bottom thereof, an electrode in said stem, a sparkl point secured to the top of said electrode and a second electrode mounted in the face of said impact wall.

4. An ignition system for oil burners of the type including a hearth, which comprises an insulator stern, an electrode therein, said stem extending through, and completely isolated by an air space from the Walls of an enlarged opening in said hearth and projecting below said hearth, an insulator cup into which said sternextends, the bottom of said cup being securd to said stem and said cup being secured to s'aid hearth and closing the opening therethrough.

5. For use with a liquid fuel burner of thegharacter whereinv combustion takes place in achamf ber having a bottom defined. by a substantially horizontally disposed hearth, said hearth having atleast one vertically extending aperture therein, means for igniting fuel in said chamber, com-v prising a vertically extending electrode of relatively small cross sectional area disposed in said aperture, a heat resistant insulating shell fitted within said aperture and spaced 'from said electrode to'provide a dielectric air space around said electrode, said shell being carried by said Ahearth and secured to said electrode at a point.

.downwardly remote from the upper surface of said hearth, to thereby protect it against the heat of combustion in said chamber.

6. The apparatus described in claim 5, wherein i said shell is shaped to prevent uid communicaf l tion between the upper and lower sides of said hearth.

, 7. The' apparatus described in claim 5, wherein said electrode comprises an inner conducting. member and an outer insulating member and 10 said shell is joined to said outer. member.

8. The apparatus described in claim 5, whereinL said shell comprises a cylindrical cupdisposed in,.-

, said aperture and having a plurality of outward#A 1y extending portions disposed in surface engage- 15 ment with the upper surface of said hearth. 3f

9. In a liquid fuel burning apparatus having a hearth and fuel vlatilizing means disposed abov the hearth surface, said hearth being provid l y with an aperture of appreciable cross section 20 area, and fuel igniting means cooperating with. said aperture, said igniting means comprising device embodying a single electrode extending through. said aperture substantially thereof and upwardly to a point well above t g@ hearth, and an insulator fitted in said aperture to snugly nil the latter, said insulator being hol.- low and in spaced relation to said electrode. th, upper end of said insulator terminating substan'ff muy flush with the upper surface of the hema;

10. In a liquid fuel burning apparatus having d' hearth and fuel volatilizing means disposed above the hearth surface, said hearth being provided' with an aperture of appreciable cross sectional area, and fuel igniting means cooperating with said aperture, said igniting means comprising an electrode extending through saidaperture sub stantially axially thereof, and an insulator iittel in said aperture in direct contact therewith and in spaced relation to said electrode, said insultan` tor comprising a shell-like wall of a length at least as great as the hearth thickness and thereby forming an annular air gap of appreciable depth around said electrode, and means for holding said electrode in position with respect to said 45 wall.

11. In the combination defined in claim 10, said positioning means comprising an integral insulating formation on the lower end of said wall. 1 50 FRANK O. CQLE. f 

